(i) Field of The Invention
This invention relates to the production of expanded metal strip and, more particularly, relates to an apparatus for gripping opposite longitudinal side edges of slit metal strip and advancing said longitudinal side edges in diverging paths for progressively laterally expanding the strip.
(ii) Description of the Related Art
A method and apparatus for forming expanded mesh sheets from deformable metal strip in which the strip is slit and pre-formed and then laterally expanded to form expanded mesh sheet is disclosed in U.S. Pat. No. 4,315,356 granted to Cominco Ltd. on Feb. 16, 1982, incorporated herein by reference. This patent discloses the forming of an upturned edge on each lateral side edge of strip to be expanded, engaging said upturned edge on each side of said strip between a pair of opposed endless chains having an internal longitudinal slot formed therein for receiving said upturned edge, and advancing said edges in laterally diverging paths by travel of said endless chains whereby the strip is progressively laterally expanded. More recently, preform protrusions have been formed adjacent each longitudinal side edge for engagement in internal longitudinal slots in the opposed endless chains. Once expansion of the metal strip is complete, a major portion of each outer longitudinal side edge of the strip containing the upturned edges or preform protrusions becomes superfluous and must be slit and discarded as scrap in order to leave a minimum width of border, if desired, for the final product. This necessitates an undesirable ancillary chopping and trimming operation and recycle of scrap with attendant losses due to creation of dross because of the presence of contaminants such as lubricating oils which must be skimmed and discarded.
It is a principal object of the present invention to provide a method and apparatus for expanding slit metal strip by gripping, guiding and transporting the opposite longitudinal side edges of the strip in diverging paths for progressively laterally expanding the strip without the need of upturned side edges, flanges, or preformed protrusions formed in the longitudinal side edges of the strip, thereby obviating an edge preforming operation and an edge slitting operation which will not only reduce equipment requirements and costs for slitting, guiding, chopping, conveying, storing and remelting steps but will also result in a reduction of about 50% or more of scrap material, depending on grid design, with a significant reduction of metal losses in lead dross.
Another important object of the invention is quick and easy access to apparatus components in a production environment for replacement of components to compensate for changes in handling characteristics of lead alloys ranging from soft low strength alloys to hard high strength alloys.